Electric lamp gas filling and sealing method and apparatus



v. A. LEVAND Aug. 25, 1959 ELECTRIC LAMP GAS FILLING AND SEALING METHODAND APPARATUS 2 Sheets-Sheet 1 .FiledJan. 28,2958

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. ViCPtOFALeV-amd, fbg I f'li-s-A 't to neg V. A. LEVAND Aug. 25', 1959ELECTRIC LAMP GAS FILLING AND SEALING METHOD AND APPARATUS Filed Jan.28, 1958 2 Sheets-Shet 2 LON ARGO/V my VDPOGEN l/4L v5) w a M w w o w oM w v m VIC 't'OT j l gvand b3 His Afi ineg HIGH AIQGON l/ALVE ELECTRICLAB [P GAS FILLING SEALING METHOD AND APPARATUS Victor A. Levant],Lyndhurst, Ohio, assignor to General My invention relates to a methodand apparatus for gas filling and sealing electric lamps and similardevices.

In the manufacture of electric lamps having a sealed envelope ofvitreous material and containing a filament or other electric energytranslation element, it has been standard practice for many years tofirst assemble the filament and envelope with lead-in conductorsconnected to the filament and extending exteriorly of the envelopethrough a seal portion thereof and with an exhaust tube connecting withthe interior of the envelope. The envelope was then exhausted andusually filled with an inert gas through the said exhaust tube which wasthen closed or tipped off by fusion to seal the envelope. More recently,certain types of tubular lamps have been made by simply flushing theenvelope through a laterally extending exhaust or supply tube with aninert gas and then sealing the respective ends of the envelope andtipping oif the supply tube, the exhaust step being eliminated.

It is an object of the present invention to provide a method andapparatus for flushing and sealing lamp envelopes without employing anexhaust or supply tube, thereby eliminating the usual tip left by theresidue of such tube and also effecting a substantial reduction in timeand materials. In accordance with one aspect of my invention, I achievethe above object by virtue of an apparatus employing a lead wire holderor chuck for supporting one or more lead-in wires extending from an endof a lamp envelope Suitably supported relative thereto, and byincorporating in association with the holder or chuck a hollow needleadapted to be inserted into the end of the lamp envelope and connectedwith a supply of inert gas to'flush or purge the interior of theenvelope. I further provide means to heat the end of the envelope to aplastic condition, and pinching jaws arranged to close and seal the endof the envelope about the lead-in wires,

together with means whereby the said needle is retracted from the end ofthe envelope just prior to the closing of the jaws thereupon.

-Further features and advantages of my invention will appear from thefollowing detailed description of a species thereof and from the drawingwherein:

Fig. 1 is a perspective view of apparatus comprising my invention;

Fig. 2 is an elevation, in section, of a lead wire holder or chuck, andshowing a lamp assembly in sealing relation thereto;

.Fig. 3-is a fragmentary elevation, partly in section, of portions ofthe lead wire chuck and pinching jaws in sealing relation to an end ofthe lamp envelope;

Fig. 4 is a schematic wiring diagram of electrically actuated componentsof the apparatus; and Fig. 5 is an elevation of a completed lamp asassembled in the apparatus.

I The apparatus is illustrated herein as employed in the manufacture oftubular lamps of the double-ended type.

The assembly of lamps parts prior to sealing, as illus- United StatesPatent O 2,900,771 Patented Aug. 25,

trated most clearly in' Fig. 2, comprises a tubular envelope 1 ofquartz, for example, and a filament assembly consisting of a coiledtungsten filament 2 having attached to each end thereof a lead-inconductor consisting of a molybdenum wire 3 having an intermediateflattened portion 4. The filament is provided with a plurality of spaceddiscs 5 of tantalum and of slightly smaller diameter than the insidediameter of the envelope, and which are secured to the filament to servethe dual functions of supporting the elongated filament in spacedrelation fiom the walls of the envelope and also serving as a getter inthe finished lamp to absorb traces of deleterious gases.

The filament assembly is held in place in the vertically disposedenvelope by an apertured cap 6 which is threaded over the lead wire 3,and the upper end of the envelope is closed off by a rubber stopperportion 7 of the cap. The lead wire 3 is gripped between an adjustablescrew 8 and the end of a clamping lever 9 which is pivoted on a pin 10and held in a normally closed portion by the expansion of a spring 11.

The lamp assembly is mounted in the apparatus by inserting the envelope1 into a holder comprising notched jaws 12 (Fig-.1) carried by a bracket13. The envelope is clamped in the jaws 12 by cooperating jaws or pads14 on the arm portion 15 of a U-shaped bracket which has its endspivoted on a pin 16 which is mounted in extensions of the bracket 13,the arms 15 being biased to closed position by springs 17 connectedbetween pins on bracket 13 and on said arms. The said bracket 13 issupported in any suitable manner from a table top 18, as by pinsor.studs 19 extending from an arm 20 secured to a block 21 mounted onposts 22 extending from the table 18..

The lamp envelope 1 is placed in the holder jaws '12, 14 with its lowerend adjacent the upper end of a lead Wire holder or chuck 23 which ismounted on table 18 in vertical alignment with said jaws. The operatorthen grasps the lead wire 3 at the lower end of the envelopewith a pairof tweezers and threads it into an axial aperture 24 (Fig. 2) intheupper end of the chuck 23. While inserting the lead wire into the chuck,the operator holds the upper end 25 of a clamping lever 26 in openposition by pressing against a button 27 on the lower end thereof topivot the lever about a pin 28 against the action of a spring 29 whichnormally biases the lever to a closed position. The operator then pullsthe envelope 1 down within the jaws 12,, 14 to bring the lower end ofthe envelope to within a few millimeters of the top of the chuck 23 asshown in Fig. 2.

The lamp envelope 1 is flushed and purged by a flow of argon gas througha hollow needle 30 which is mounted on a tube 31 for vertical andlongitudinal reciprocation in the chuck 23 and is supplied with argonthrough a conduit 32. The needle 30 is raised into the envelope byupward pivotal movement of a-lever 33 to the position shown in Fig. 1.The lever 33 pivots about a pin 34 to carry upward a bracket 35 which isconnected thereto by a pin 100 and which is fastened to a shaft 36 whichis connected to the tube 31 carrying the needle 30. The upward movementof lever 33 also actuates a normally open microswitch 37 which actuatesa sole noid valve to turn on the high pressure flow of argon gas throughthe conduit 32 and needle 30. The flowing argon gas. displaces the airfrom the envelope 1 in a stream flowing out the upper end of theenvelope while cap 6 is momentarily raised. With its replacement tonormal closed off position, the argon gas is then forced out the lowerend of the envelope. The lower end of the envelope 1 is then heated byseries from opposed burners 40 which are supplied with 1 of-r'ods 43which are mounted on a shaft 44 which pivots in a bracket 45 mounted onthe table 18. The burner is in each case supported by an arm 46 which isfixed at one end to shaft 44 and carries at its other end a roller 47which rests on a T-shaped cradle '48 constituting part of the pinchingjaw mechanism.

After a predetermined period during which the lower end of the envelopeis heated to plasticity by burners 40, with argon continuously flowingthrough needle 30, the said needle is retracted downwardly into thechuck 23 and the end of the envelope is pinched and sealed about thelead wire 3 by a pair of opposed pinching jaws 49.

The pinch jaws 49 are each carried by a cradle member 48 which ispivotally connected at its back end to one end of a link 50 which ispivoted at its other end on a pin 51 journalled in a bearing plate 52 onthe table 18. The depending stem or arm portion of the T-shaped cradle48 is pivotally connected to one end of a link 53 which is pivoted on apin 54 journalled in the plate 52. The pinch jaws 49 are closed when thecradle 48 is rocked upwardly and forwardly by an arm 55 which isattached at one end to the link 53 and is pivotally connected at itsother end to the upper end of a connecting rod 56 which is connected atits lower end to a pin 57 which engages a slot in the lever 58.

The lever 58 is pivoted on the pin 34 and is swung downwardly by an aircylinder 59 to pull down the rods 56 and thereby cause the pinch jaws 49to close. At the same time, the pin 57, by engagement with the lower endof a slot 60 in the bracket 35, pulls the bracket downward to therebyretract the argon needle 30 just before the jaws 49 close upon theenvelope 1. Also at the same time, the high pressure flow of argon isshut otf when lever 33 is pulled down by bracket 35 to release theswitch 37. Upon subsequent release of air pressure in the cylinder 59,the lever 58 is pulled upward by a spring 61 to cause the pinch jaws 49to open; however, the argon needle 30 remains in its retracted positionas the pin 57 slides upwardly through the slot 60 in bracket 35.

After the seal has been completed, the lamp is quickly removed from theholder jaws 12, 14, turned end-forend, reinserted in the jaws 12, 14,the cap 6 is removed, the then lowermost lead wire 3 is threaded intothe chuck 23, the envelope 1 is pulled down close to the chuck 23, andthe operations of flushing, heating and pinching are repeated to formthe finished lamp shown in Fig. with both ends sealed to enclose theargon gas as the final filling gas.

Fig. 4 is a schematic diagram showing means for semiautomatic operationof the apparatus. With the apparatus at rest, wherein the jaws 49 areopen and the needle 30 is retracted into the chuck 23, the operatorcloses the main switch 64 whereby a solenoid valve 65 is energized viaconductors 66, 67 and 68 and is opened to admit a low presure flow ofargon gas to the conduit 32 and needle 30. At the same time, electronictimers T1 and T2 are connected into the circuit across main conductors66 and 68 via respective conductors 69 and 70.

After the lamp assembly, including envelope 1 and attached cap 6, hasbeen inserted in the holder jaws 12, 14 and the lower lead wire 3clamped in chuck 23, the needle 30 is raised to the position shown inFigs. 1 and 2 by pivoting upward the lever 33 to raise the bracket 35,rod '36 and tube 31 carrying the needle 30. This movement of the lever33 closes the microswitch 37 which energizes a solenoid valve 71 viaconductor 72 to start a high pressure flow of argon through the conduit32 and needle 30 to purge the air which flows through the envelope. I I

The operator then closes a push button switch 73 to energizethe coil 74of a holding relay through normally closed contacts 75 in timer T2; thecircuit is made from main conductor 66 through conductor 67, switch 37,cona} ductor 76, switch 73, conductor 77, conductors 78 and 82, coil 74,conductor 79 and contacts 75 to main conductor 68. The contact 80 of theholding relay is thereby closed to maintain its coil 74 energized by wayof main conductor 66, conductor 81, contact 80, conductors 78 and 82,coil 74, conductor 79, contacts 75 and main conductor 68.

At the same time that the holding relay 74 is energized, the flow ofoxygen and hydrogen is started to the burners 40 by energization ofsolenoid valves 83 and 84 (Fig. 4) in the supply lines 41 and 42, theburners being ignited by pilot flames (not shown). The circuit tosolenoid valves 83 and 84 is completed via conductors 66, 67, switch 37,conductor 76, switch 73, conductors 77, 85, 86, contact 87 of relay 74and conductor 88; the circuit is maintained, after energization of relaycoil 74, by the closure of its Contact 80 to form a shunt circuit aroundswitch 73 via conductor 81, contact 80,

and conductor 78. Also at this time, the coil 89 of a relay 90 isenergized by way of conductors 77 and 86 to close its contact 91 andthereby start the timer T1.

At the end of the predetermined time setting of the timer T1 its pairsof contacts 92 and 93 are closed. The closing of contacts 92 starts thetimer T2. The closing of contact 93 actuates a solenoid valve 94 in theair line to the cylinder 59 by way of contacts 95 in timer T2 andconductors 96, 97 and 98. The actuation of air cyl inder 59 causes thepinch jaws 49 to close upon the heated lower end of the envelope andseal it as shown in Fig. 3; it also eifects retraction of the argonneedle 30 from the envelope 1 just before the jaws 49 close upon it. Theclosing of the jaws 49 occurs when the rod 99 (Fig. 1), connected to thepiston of air cylinder 59 and to lever 58, is depressed to pivot thelever 58 downward and pull the connecting rods 56 downward to cause thejaws 49 to be closed through arms 55, links 53 and arms 48. The downwardpivoting of lever 58 also pulls downward the bracket 35 which isconnected to needle 30 by rod 36 and tube 31. The high pressure supplyof argon gas through needle 38 is terminated when lever 33 is pulleddown by virtue of its connection to bracket 35 by pin 100 to therebyrelease the microswitch 37 and de-energize the solenoid valve 71.However, the low pressure fiow of argon continues to provide aprotective non-oxidizing atmosphere around the portion of lead wire 3outside the envelope 1.

At the end of the predetermined time setting of the timer T2, itscontacts 75 are opened to thereby de-energize the system including thecoil 74 of the holding relay. Accordingly, the burners 40 areextinguished by virtue of de-energization of the oxygen and hydrogensolenoid valves 83 and 84, the relay 90 is de-energized, and thecontacts 95 in timer T2 are opened to de-energize the solenoid valve 94in the supply line to air cylinder 59 to thereby permit the lever 58 tobe raised by spring 61 to open the pinch jaws 49. During the upwardreturn of lever 58, the bracket 35 remains downward since pin 57 slidesupward in slot 60 so that the argon needle 30 remains down.

The envelope 1 is then quickly removed from holder jaws 12, 14 andinverted and replaced in those jaws; the cap 6 is removed from the thenlower end of the envelope l, the then lower lead wire 3 is inserted andclamped in the chuck 23, the argon needle 30 is raised by pulling upwardthe lever 33, and the flushing and sealing cycle is repeated asdescribed above. When these operations are performed within about 10 to15 seconds there is not sutficient time to permit the heated portionor"- the envelope 1 to cool sufliciently to draw in an appreciableamount of air, so that the subsequent purging by flow of argon throughneedle 30 assures a purified atmosphere of argon in the envelope whichis retained therein to constitute the permanent gas filling after thesecond end of the envelope has been sealed.

The finished lamp appears as shown in Fig. 5. However, it will beunderstood that, particularly when shorter envelopes 1 are employed, theapparatus may be employed to flush and seal single-ended envelopeshaving only one end thereof open.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. In apparatus for flushing and sealing an electric lamp assembly, thecombination of a chuck member adapted to hold a lead-in conductor, meansto support a vitreous lamp envelope in alignment with said chuck andwith an end thereof enclosing the portion of said conductor projectingfrom said chuck, means adjacent said chuck for heating the said end ofthe envelope to plasticity, pinching jaws mounted adjacent said chuck, ahollow needle mounted in said chuck for reciprocable movement into andout of said end of the envelope, means connecting said needle to asupply of flushing gas, and means for actuating said needle and saidpinching jaws in synchronism to cause said needle to be retracted fromthe envelope into said chuck and to then immediately cause said jaws toclose upon said end of the envelope to compress and seal it about thesaid lead-in conductor.

2. In apparatus for flushing and sealing an electric lamp assembly, thecombination of a chuck member adapted to hold a lead-in conductor, meansto support a vitreous lamp envelope in alignment with said chuck andwith an end thereof enclosing the portion of said conductor projectingfrom said chuck, means adjacent said chuck for heating the said end ofthe envelope to plasticity, pinching jaws mounted adjacent said chuck, ahollow needle mounted in said chuck for reciprocable movement into andout of said end of the envelope, a supply of flushing gas adapted to beconnected with said needle, means for moving said needle out of saidchuck to project into an envelope held by said support means, meansoperable upon movement of said needle into the envelope to eifectconnection of said supply of gas with the needle, and means foractuating said needle and said pinching jaws in synchronism to causesaid needle to be retracted from the envelope into said chuck and tothen immediately cause said jaws to close upon said end of the envelopeto compress and seal it about the said leadin conductor.

3. The method of gas filling and sealing an electrical device comprisingan envelope of vitreous material having an open end which comprisesholding a lead-in wire to extend into said envelope through said openend thereof, inserting a hollow needle into said envelope alongside saidlead-in wire, flowing an inert gas through said needle into saidenvelope to flush the interior thereof and expel the air therefrom,heating the said end of the envelope to a plastic condition, and thenretracting the needle from said envelope and immediately pinching theheated end to compress and seal it around said lead-in wire with theinert gas retained in the envelope.

4. In apparatus for flushing and sealing an electric,

lamp assembly, the combination of holder means adapted to support alead-in conductor, support means for sup porting a vitreous lampenvelope in alignment with said holder means and with an end thereofenclosing a portion of said conductor projecting from said holder means,heater means adjacent said holder means for heating the said end of theenvelope to plasticity, pinching jaws mounted adjacent to said holdermeans, a hollow needle, means mounting said needle adjacent said holdermeans for reciprocable movement into and out of the end of saidenvelope, means connecting said needle to a supply of flushing gas, andmeans for actuating said needle and said pinching jaws in synchronism tocause said needle to be retracted from said envelope and to thenimmediately cause said pinching jaws to close upon said end of theenvelope to compress and seal it about the said lead-in conductor.

Payne Dec. 7, 1937 Freeman Feb. 17, 1942

